From: Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com>
Newsgroups: sci.chem
Subject: Re: Questions on Soft Clear PVC & Plastics
Date: 24 Feb 1996 23:07:57 GMT

Poly(vinyl chloride) neat is a clear, glass-like resin.

Finely powdered PVC resin in, for instance di-octyl phthalate, is fairly 
stable at room temp.  If you heat it up in a mold the ester dissolves in 
the polymer and the whole mass fuses into a soft (depends upon how much 
and what plasctizer) whole.  Consider Tygon tubing or shower curtains.  
Plasticized PVC has wonderful short-term physical properties, it is 
biologically inert, cheap to manufacture, and valued-added to sell.

The entire planet is contaminated with phthalate plasticisers slowly 
blooming from untold gigatons of plastized PVC, Naugahyde and whatnot.  
The oily stuff which deposits inside your auto's windshield is 
plasticizer from your plastic upholstery.

Now comes the fun part.  Oddly enough, just about every class of chemical 
which strongly triggers a gas chromatograph's electron capture detector 
has many members which are potent mutagens by the Ames test, and which 
show other inimical chronic biological effects.  Phthalates make EC 
detectors shoot off-scale, but appear to be harmless - maybe.  They also 
resist environmental degradation and concentrate in body fat, amplifying 
up the food chain.

PVC itself is a real nuisance at disposal time.  Burning PVC relases vast 
amounts of HCl, which corrodes incinerators.  PVC and PET are hard to 
distinguish.  Only a few ppm of PVC in recycled PET turns nice white PET 
insulation fluff into black crud.

-- 
Alan "Uncle Al" Schwartz
UncleAl0@ix.netcom.com  ("zero" before "@")
http://vvv.com/adsint/freehand/uncleal/
"Quis custodiet ipsos custodes?"  The Net!